An optical pickup device is configured to focus a light beam on an information layer of an optical disk using an objective lens. The information layer of the optical disk is covered by a transparent cover layer, and it is known that a wave aberration (spherical aberration) occurs if there is a variation in thickness of the cover layer. In order to correct the wave aberration, it is proposed to move a collimator lens to correct the divergence/convergence angle of the light flux incident on the objective lens (see Patent Document No. 1). Further, it is also proposed to move a relay lens to correct the divergence/convergence angle of the light flux incident on the objective lens (see Patent Document No. 2).
Patent Document No. 1: Japanese Laid-Open Patent Publication No. 2004-103087 (Pages 5-6, FIG. 1).
Patent Document No. 2: Japanese Laid-Open Patent Publication No. 2003-338069 (Page 5, FIGS. 1-5).